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ASF GitHub Bot logged work on HIVE-27186: ----------------------------------------- Author: ASF GitHub Bot Created on: 19/Apr/23 12:38 Start Date: 19/Apr/23 12:38 Worklog Time Spent: 10m Work Description: dengzhhu653 commented on code in PR #4194: URL: https://github.com/apache/hive/pull/4194#discussion_r1171276457 ########## standalone-metastore/metastore-common/src/main/java/org/apache/hadoop/hive/metastore/properties/Serializer.java: ########## @@ -0,0 +1,207 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance + * with the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ +package org.apache.hadoop.hive.metastore.properties; + +import org.slf4j.Logger; + +import java.io.File; +import java.io.IOException; +import java.io.InputStream; +import java.io.ObjectInput; +import java.io.ObjectInputStream; +import java.io.ObjectOutput; +import java.io.ObjectOutputStream; +import java.io.OutputStream; +import java.io.Serializable; +import java.nio.file.Files; + +/** + * A helper class to read/write objects through the SerializationProxy. + * + * @param <T> + */ +public class Serializer<T extends Serializable> { + private static final Logger LOGGER = SerializationProxy.LOGGER; + Review Comment: There is a `SerializationUtilities` for the same purpose, can we reuse this utils? Issue Time Tracking ------------------- Worklog Id: (was: 857933) Time Spent: 2h 50m (was: 2h 40m) > A persistent property store > ---------------------------- > > Key: HIVE-27186 > URL: https://issues.apache.org/jira/browse/HIVE-27186 > Project: Hive > Issue Type: Improvement > Components: Metastore > Affects Versions: 4.0.0-alpha-2 > Reporter: Henri Biestro > Assignee: Henri Biestro > Priority: Major > Labels: pull-request-available > Time Spent: 2h 50m > Remaining Estimate: 0h > > WHAT > A persistent property store usable as a support facility for any metadata > augmentation feature. > WHY > When adding new meta-data oriented features, we usually need to persist > information linking the feature data and the HiveMetaStore objects it applies > to. Any information related to a database, a table or the cluster - like > statistics for example or any operational data state or data (think rolling > backup) - fall in this use-case. > Typically, accommodating such a feature requires modifying the Metastore > database schema by adding or altering a table. It also usually implies > modifying the thrift APIs to expose such meta-data to consumers. > The proposed feature wants to solve the persistence and query/transport for > these types of use-cases by exposing a 'key/(meta)value' store exposed as a > property system. > HOW > A property-value model is the simple and generic exposed API. > To provision for several usage scenarios, the model entry point is a > 'namespace' that qualifies the feature-component property manager. For > example, 'stats' could be the namespace for all properties related to the > 'statistics' feature. > The namespace identifies a manager that handles property-groups persisted as > property-maps. For instance, all statistics pertaining to a given table would > be collocated in the same property-group. As such, all properties (say number > of 'unique_values' per columns) for a given HMS table 'relation0' would all > be stored and persisted in the same property-map instance. > Property-maps may be decorated by an (optional) schema that may declare the > name and value-type of allowed properties (and their optional default value). > Each property is addressed by a name, a path uniquely identifying the > property in a given property map. > The manager also handles transforming property-map names to the property-map > keys used to persist them in the DB. > The API provides inserting/updating properties in bulk transactionally. It > also provides selection/projection to help reduce the volume of exchange > between client/server; selection can use (JEXL expression) predicates to > filter maps. -- This message was sent by Atlassian Jira (v8.20.10#820010)